Spray gun



Sept. 4, 1951 J.'A. WILKINS EI'AL SPRAY GUN Filed June 20, 1945 PRESS URE FL (J'ID INVENTORS Jo/m A. Wil/nhs By David Wf/lrins, Jr. M LL A TTORNEY Patented Sept. 4, 1951 SPRAY GUN J ohn A. Wilkins and David Wilkins, J r., New York, N. Y.

Application June 20,1945, Serial-No. 600,628

(Granted under the act of March 3, 1883, as

3 Claims.

. amended April 30, 1928; 370 0. G. 757) This invention relates to the art of spray guns, and it comprises a spray gun particularly useful for spraying heavy, thick compositions, and rela tively large quantities thereof. Ships bottoms, for example, are commonly coated with thick, pasty compositions which cannot be handled by conventional spray guns, or can be handled only with great difficulty and at an extremely slow rate.

An object of this invention is to provide a spray gun that will atomize and spray heavy, thick, and pasty compositions.

Another object is to provide a spray gun that will atomize and spray at a high volumetric rate.

Still another object is to provide a spray gun that will effectively. coat surfaces at a relatively great distance from. the nozzle end of the spray gun.

Further objects and advantages of this invention, as well as its construction, arrangement and operation, will be apparent from the following descriptions and claims in connection with the accompanying drawing, in which,

Fig. 1 is an elevation of a spray gun embodying the present invention.

Fig. 2 is an elevation of the spray gun of Fig. 1, viewed from the left of Fig. 1.

Fig. 3 is an end view of the spray gun of Fig. 2, and looking toward the nozzle orifices.

Fig. 4 is a detailed cross-sectional elevation taken along the line 4-4 of Fig. 2.

Fig. 5 is a perspective view of a portion of the pressure-fluid and composition tubes together with their control valves.

The tube I4 comprises a duct for the passage of coating composition such aspaint or other suitable material to be sprayed by means of the device of the present invention, and it is preferably made of brass or similar corrosion-resistant material. Valve I2 is the means by which the flow of coating composition through tube I4 is controlled. The pressure fluid duct is also preferably made of brass or similar corrosion-resistant material and it comprises a single duct including a valve I5, beyond which it is bifurcated to form the tubes I3 parallel to the composition tube I4 and disposed adjacent thereto on opposite sides thereof, the axes of the air tubes I3 and the composition tube I4 being preferably coplaner. The valve I5 regulates and controls the flow of air through the tubes I3.

A concentric bushing l6 having a concentric cylindrical bore is fixed in the end of composition tube I4 to comprise a nozzle therefor, the bore in the bushing I6 providing a cylindrical orifice of 2 predetermined diameter to predeterminethe flowrate of the stream of coating composition emergingtherefrom. A flexible hose I'I conducts coating composition under pressure from a conventional pressurized reservoir (not shown) to the composition tube I4, and pressurized air is conducted from any conventional source through a flexible hose I8 to the duct that includes valve I5, thence to the tubes [3.

The tubes I3 are deflected or bent towards each other near their ends to form nozzles 22, which are thus directed to intersect each other and the axis of nozzle I6 at a point beyond and closely adjacent the composition nozzle. Each nozzle 22 is directed at an angle less than 45 with reference to the axis of nozzle. I6 so that there is an acute angle between the nozzles 22. An angle of about 30 is preferred between the composition nozzle I6 and each pressure-fluid nozzle 22, and an angle of about between the nozzles 22. See Figs. 1 and 4.

. The nozzle I6 of composition tube II and nozzles 22 of air tubes I3 are held in fixed relationship by a welded or brazed joint I 9, and the ducts upon which valves I2 and I5 are mounted are suitably spaced and rigidly held by a block 20 located adjacentthe upper ends of the ducts as viewed in Fig. 2, and inserted. between them and suitably fastened as by welding or brazing. It will be apparent that suitable clips or equivalent devices may be utilized to join the component parts of the subject invention and hold them in the desired relationship. 7

The nozzles 22 are formed by flattening each air tube [3 at its nozzle end, and the orifice of each nozzle 22 is therefore oblong and approximately rectangular. .By approximately rectangular, it. is meant that the openings are elongated and have substantially parallel sides. The ends of the openings may be square, rounded, or otherwise shaped as desired. The long dimensions of the openings of nozzles 22. are normal to the common plane of the axes of air tubes I3 and composition tube I4 in the embodiment of the disclosure. The flat walls of the nozzles 22 may be parallel for a suitable distance from the nozzle openings or may converge slightly toward the nozzle openings. The bends in the air tubes I3 Where the nozzles 22 begin are preferably smooth and of large radius. The shape of nozzles 22, it will be apparent, is such as to form fiat streams of air, directed toward each other so as to converge at an acute angle.

The inside surface of bushing I6 is smooth and well tapered so as to offer as little resistance as I from its axis.-

, pingement of the air streams.

V coating composition. r

In the operation of the portable spray gun of the present invention, valve I5 is opened and pressurized air is permitted to flow through air tubes 13 and out the elongated openings of their nozzles 22. suificient length back from their nozzles 22 to Air tubes 13 should be straight for a insure that air at the nozzle ends will not be moving in turbulent flow. Upon valve l2 being opened, a stream of coating composition will be forced into the impinging flat streams in their area of impingement, and will be broken into an extremely fine spray and impelled outward.

Using a coating composition of moderately i heavy consistency, an air pressure of 100 pounds .per square inch, and.the same pressure behind the coating composition in composition tube ll, one obtains an excellent spray which will travel several feet without. excessive divergence. The long carry of this spray enables an operator to cover a large area with a minimum of movement, and reduces the complexity and size of the scaffolding reouired for many jobs. Lesser and greater pressures may be used, as available and as desired. Optimum pressures will vary with the consistencv of the coating composition being applied, the thickness of coat desired, air temperature and other factors.

The oblong openings of nozzles 22 must be wide enough so that the flow of air through them is not unduly restricted, and yet narrow enough so that the stream of air issuing therefrom has a definite fiat form, a Width of from 10' to 50% of ,the length of the openings being suitable.

he longer dimension of the orifice of each tube I3 extends further from its nozzle axis in both directions than the orifice of bushing 16 extends Thelength of the air openings must be sufficientl greater than the diameter of 'the opening in bushing 16 to insure that the entire stream ofcoating composition emerging from composition tube II iscaught in thearea of im- As long as the relative proportions of the oblong air openings are maintained, the diameter of the nozzle opening of bushing l6 may be made as large as necessary to attain any desired rate of flow of the It is to be understoodthat various modifications and changes maybe made in this invention without departing from the spirit and scope thereof as set forth in the appended claims.

. The invention described herein may be manufactured and used by or for the Government of '4 the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is: 1. In a portable spray gun, a tube for the composition to be sprayed-comprising a nozzle at its end, the nozzle comprising. a cylindrical orifice; a plurality of tubes for pressure fluid, each pressure-fluid tube being flattened at its end to form a nozzle comprising an oblong orifice, the pressure-fluid and composition tubes being rigidly secured in positions adjacent each other at their nozzle end portions to locate the several pressurefiuid. nozzles symmetrically on respectively opposite sides of the composition nozzle, the longer dimension of each oblong pressure-fluid orifice extending transversely of a line through the centers of the nozzle orifices of the several pressurefluid and composition nozzles and beyond the span of the composition nozzle, each of the pressure-fluid tubes being bent near its nozzle end to direct its nozzle toward the axis of the composition nozzle to intersect the composition nozzle axis at a point beyond and closely adjacent the composition nozzle, whereby the composition flowing from the composition nozzle is broken into a spray and impelled outwardly and away from said nozzles.

2. In a spray gun as defined in claim 1, the composition nozzle comprising a bushing having a concentric cylindrical bore, and thebushing being secured inthe end of the composition tube.

J 3. In a spray gun asdefined in claim 1, the axis of each pressure-fluid nozzle being directed to intersect the axis of the composition nozzle at an angle of approximately 30 degrees.

JOHN A. WILKINS. 1 DAVID WILKINS, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 7 Name Date 328,227 Kennedy et al. Oct. 13, 1885 1,092,785 Stene et al. Apr. 7, 1914' 1,490,683 .Straitz .Apr. 15, 1924 1,751,787 Binks Mar. 25, 1930 1,881,345 Beatty etal. Oct. 4, 1932 1,936,997 String Nov. 28, 1933 1,968,992 Conkling Aug. 7, 1934 2,088,542 'Westin July 27, 1937 2,136,024 Schneider Nov. 8, 1938 2,255,189 Robinson et a1 Sept. 9, 1941 2,261,279 Pellar Nov. 4, 1941 2,335,116 Hansen Nov. 23, .1943

' FOREIGN PATENTS Number Country Date 145,168 7 Great Britain June 30, 1920 290,036 Great Britain May 10, 1928 

